Gearbox type:
Selected gear:
Actual gear ratio: * final drive
Revs: revs/min

Actual tyre size: / R
Actual wheel circumference: m
Road speed: km/h, miles/h.

Standard tyre size: / R
Standard wheel circumference: m, difference will cause % misreading on speedometer.


- Select your gearbox type (page will fill out tyre sizes as well).
- Select the gear.
- Enter the revs.
- Now you can see what speed belongs to the given gear ratios and tyre size.
- If you change actual tyre size, you can check what difference it will make to speedo reading.
- If you change road speed, page will calculate the appropriate revs based on the gear ratios and tyre size.
- If you want to change gear ratios, just enter the desired values into the "ratio" line.
- I plan to add more gearboxes later (MA boxes for TU engines, diesel ones, Mi16). If you have comments, you can mail me.